of eaeh Level involved, | Normally the levels covered were in ten thousand feet increments; however, not every such level was given. Rather the attems was ta cover those levels of interest up to about fifty to sixty thousand feet, presenting the levels having a unique or significant orientation, or those levels which bounded, or most nearly represented, the drift of the tain portion of the cloud. althougy trajectories for significant levels were passed to CINCP.CFLT (and revised if necessary) the decisions as to the effect of each situation alse included consideration of the following factors: (a) Flight levels within the first 20,000 feet were considered of prinary concern. (b) The orientation of levels above 20,000 feet (from wiich contamination could fall inte the lower i vel) were evaluated in terms of time and geographical position of settling of contamination into normal flight levels. . (c) Recommended closure times and altitudes included estinat- ed flight times between possible departure points and the forecast positions of contamination, (d) Forecast trajectory position beyond twenty-four hours were considered to represent positions of insignificant contamination, (e) Cloud tracking operations post-shot were analyzed for poseible impact on the pre-shot decision. (3) Protection of transient shipping: In order to provide pro= tection for transient shipping in the region immediatelyoutside the ENTWETOKBIKINI Danger .rea, planning factors were established and a plen of action placed in effect as follows: (a) C.STLE clouds more than twenty-four hours old were not 32